Metal-free acylated organic phosphate complexes as corrosion inhibitors



United States Fatent O 3,216,956 METAL-FREE ACYLATED ORGANIC PHOSPHATECOlWPLEXES AS CDRROSION INHIBITORS Willis G. Craig, Willoughby, Ohio,assignor to The Lubrizol Corporation, Wicklilfe, Ohio, a corporation ofOhio N Drawing. Filed Feb. 21, 1962, Ser. No. 174,691 11 Claims. (Cl.260-23) The present invention relates to novel, metal-free, acylatedorganic phosphate complexes and processes for their preparation. In amore particular sense, it relates to corrosion-inhibiting coatingcompositions for metals comprising the aforesaid complexes.

The corrosion of metal surfaces is of obvious economic significance inmany industrial applications and, as a consequence, the inhibition ofsuch corrosion is a matter of prime consideration. It is particularlysignificant to users of steel and other ferrous alloys. The corrosion ofsuch ferrous metal alloys is largely a matter of rust formation, whichin turn involves the overall conversion of the free metal to its oxide.

The theory which best explains such oxidation of ferrous metal surfacespostulates the essential presence of both water and oxygen. Even minutetraces of moisture are sufiicient, according to this theory, to inducethe dissolution of iron therein and the formation of ferrous hydroxideuntil the water becomes saturated with ferrous ions. The presence ofoxygen causes oxidation of the resulting ferrous hydroxide to ferrichydroxide, which then settles out of solution and is ultimatelyconverted to ferric oxide or rust.

The above sequence of reactions can be prevented, or at least in largemeasure inhibited, by relatively impermeable coatings which have theeffect of excluding moisture and/or oxygen from contact with the ferrousmetal surface. Such coatings are, of course, subject to abrasion andother forms of physical deformation and to the extent that thesecoatings are penetrated or otherwise harmed by such influences theybecome ineffective for the desired purpose. It is important that suchcoatings provide complete protection for all of the ferrous metalsurface. If there is any portion of such a surface which is not soprotected, regardless of hoW small the unprotected surface may be, thedegree of protection afforded is considerably less than required. Asatisfactory corrosion-inhibiting coating then must have the ability toresist weathering, abrasion, chalking or powdering, alligatoring, andundercutting so that a uniform and complete protective film ismaintained upon the metal surface. Alligatoring and undercutting areterms commonly used in the protective coating art to describe,respectively, the shrinkage of a coating to form a discontinuous, brokensurface having a pattern akin to that of alligator skin and theseparation of a coating from the metal substrate in the area adjacent toa scratch or score. In some instances, undercutting may be so severethat most, if not all, of the coating separates from the metalsubstrate.

Various derivatives of acid esters of phosphoric or phosphorothioicacids have been investigated by workers engaged in the task of providingprotective coatings for metal. In U.S. Patent 2,080,299, for example,Benning et al. proposed the treatment of ferrous metals with phosphateacid esters or their alkali metal and ammonium salts to prevent rusting.Somewhat similarly, Butler and Le Suer (US. Patents 2,861,907 and2,820,723) find that salt-esters of complex phosphorothioic acids areeffective in preventing or retarding the corrosion of metals.

Although such known derivatives of phosphoric and phosphorothioic acidshave provided means for combatting the corrosion of metals, they havenot been completely satisfactory because of certain inherentshortcomings. The simple salt-esters of phosphoric acid are read- 3,216,956 Patented Nov. 9, 1965 ily washed or abraded from a metallicsurface and thus provide complete protection only in a favorableenvironment. The saltesters of phosphorothioic acids, on the other hand,have the disadvantage, under certain conditions, of developing anobjectionable odor reminiscent of hydrogen sulfide, particularly when afilm of such a salt-ester comes in contact with water or humidatmospheres.

A further disadvantage of these known derivatives of phosphoric andphosphorothioic acids is that they form oily or tacky coatings which arenot susceptible to the subsequent application of top-coats of siccativeorganic coating compositions such as paint, varnish, lacquer, enamel,and the like. Thus, their use has been limited to metal articles such asbulk castings, metal fasteners, firearm parts, iron cables, etc., whichdo not require a hard-film protective coating.

It is, therefore, a principal object of the present invention to providenovel, acylated organic phosphate complexes and processes for theirpreparation.

Another object is to provide corrosion-inhibiting coating compositionsfor metals, especially ferrous metals, which compositions compriseacylated organic phosphate complexes.

A further object is to provide novel coating compositions for metals,which compositions are resistant to weathering, abrasion, chalking,alligatoring, and undercutting.

A still further object is to provide means for improving thecorrosion-inhibiting characteristics of known, siccative, organiccoating compositions.

These and other objects of the invention are achieved by providing anacylated organic phosphate complex prepared by the process whichcomprises the reaction of:

(A) One mole of a phosphorus-containing reagent se lected from the groupconsisting of phosphorus pentoxide and phosphoric acids.

(B) From about 0.2 to about 5 moles of a copolymer of allyl alcohol anda styrene,

(C) From about 0.5 to about 5 moles of an alkyl phenol,

and

(D) From about 0.5 to about 4 moles per mole of (B) employed of anunsaturated aliphatic carboxylic acid compound selected from the groupconsisting of high molecular weight unsaturated aliphatic carboxylicacids containing at least about 12 carbon atoms and esters of suchacids,

at a temperature within the range from about 50 C. to about 300 C. forabout 0.5 to about 30 hours.

The term strong acid number as used herein denotes the number ofmilligrams of potassium hydroxide required to neutralize one gram ofsolvent-free reaction mixture in the presence of an indicator such asbromphenol blue or methyl orange which changes color in the region of pH4. Acid-base neutralizations or titrations conducted in this mannermeasure acidity due to acid phosphates, but do not measure acidity dueto carboxylic acids.

Thin films of the acylated organic phosphate complexes of the presentinvention are remarkably effective in protecting metal surfaces,especially ferrous metal surfaces, against the ravages of corrosion. Thecomplexes are also useful as ingredients in known, siccative, organiccoating compositions such as paints, varnishes, lacquers, primers,synthetic resins, and enamels, to which compositions they impartenhanced corrosion-inhibiting characteristics. When used in this manner,a minor proportion, generally from about 0.1 to about 25 percent, of anacylated organic phosphate complex of this invention is blended with amajor proportion, generally from about 99.9 to about percent, of asiccative organic coating composition.

3 REAGENT A As indicated earlier, the phosphorus-containing reagent A isselected from the group consisting of phosphorus pentoxide andphosphoric acids. For reasons of conven-ience, economy, and reactivityin the process of the invention, phosphorus pentoxide is generallypreferred.

Where it is desired to employ phosphoric acids, any of the severalavailable phosphoric acids such as polyphosphoric, orthophosphoric,metaphosphoric, or pyrophosphoric acid may be used either alone or inadmixture as this reagent. It is also feasible to use mixtures ofphosphorus pentoxide with one or more of these phosphoric acids.Phosphoric acid, if employed, will generally be the ordinary, commercial85 percent or 100 percent orthophospho-ric acid, although more diluteacids containing at least about 25 percent H PO are also usable.

REAGENT B This reagent is a copolymer of to 90 mole-percent of allylalcohol with 90 to 10 mole-percent of a styrene. Especially useful forthe purposes of this invention are copolymers prepared fromapproximately equimolar amounts of the two monomers and having anaverage molecular weight within the range from about 500 to about 5,000.

A particular preference is expressed for a copolymer of approximatelyequimolar amounts of allyl alcohol and styrene having an averagemolecular weight of about 1,'l00l,l50. Such a copolymer is availablecommercially under the trade designation, Polyol X-450. Similarcopolymers of lesser or greater average molecular weight are alsoavailable commercially such as Monsanto RI- 100, which has an averagemolecular weight of about 1,580.

The term a styrene as used herein refers to styrene or any of thevarious substituted styrenes such as halogen-substituted styrenes,hydrocarbon-substituted styrenes, alkoxy-styrenes, acyloxy-styrenes,nitro-styrenes, etc. Examples of such substituted styrenes includep-chloro styrene, p-ethylstyrene, o-phenylstyrene, p-methoxystyrene,m-nitrostyrene, alpha-methylstyrene, and the like. In most instances,however, it is preferred to use styrene itself by reason of its lowcost, commercial availability, and excellence as a raw material in thepreparation of reagent B.

REAGENT C This reagent may be either a mono-alkyl or a polyalkyl phenol.The alkyl groups may be of any size, ranging from methyl up to alkylgroups derived from olefin polymers having molecular weights as high as50,000 or more. Preferably the alkyl phenol is a mono-alkyl phenol inwhich the alkyl group contains from one to about 30 carbon atoms,preferably at least about 4 carbon atoms. Typical examples of usefulalkyl phenols include, e.g., ortho, meta, and para-cresols; ortho, meta,and paraethyl phenols; para-isopropyl phenols, para-tertiarybutylphenol, ortho n-amylphenol, para-tertiary amylphenol, heptylphenol,diisobutylphenol, n-decylphenol, wax-alkyL ated alpha-naphthol,wax-alkylated phenol, and polyisobutene-substituted phenols in which thepolyisobutene substituent contains from about 12 to about 76 carbonatoms. The alkyl phenol may also contain substituent groups such as,e.g., chloro, fluoro, nitro, alkoxy, sulfide, nitroso, etc. A particularpreference is expressed for para-tertiary amylphenol, a compound whichis available under the trade designation Pentaphen. Also useful arepolyhydric phenols such as alkylated resorcinols, alkylated catechols,alkylated pyrogallols, and their substitution products.

REAGENT D Reagent D, the unsaturated aliphatic carboxylic acid compound,is a high molecular weight unsaturated aliphatic carboxylic acidcontaining at least 12 carbon atoms and/ or an ester thereof.Illustrative of materials useful as this reagent includes, for example,linoleic acid, linolenic acid, linseed oil, tung oil, tung oil acids,methyl linoleate, ethyl linolenate, chloroleic acid, phenyloleic acid,oleic acid, behenolic acid, palmitolic acid, ricinoleic acid,ricinstearolic acid, and mixtures of any of the foregoing.

Especially preferred are the unsaturated aliphatic carboxylic acids and/or esters thereof which contain at least two carbon-to-carbon doublebonds such as linoleic acid, linseed oil, and linolenic acid. Aparticular preference is expressed for linoleic acid and tung oil, bothof which are readily available, staple articles of commerce. It is notnecessary that the unsaturated acids and/or esters thereof be chemicallypure materials. Crude linoleic acid obtained, for example, from theprocessing of tall oil has been found to be very suitable as reagent Dherein.

The process for the formation of the acylated organic phosphate complexmay be carried out in any one of several different ways such as, forexample: (1) preparing a mixture of reagents A, B, C, and D and thenheating such mixture at a temperature within the range from about 50 C.to about 300 C., preferably from 80160 C., for about 0.5 to about 30hours; (2) heating reagent B, the copolymer of allyl alcohol and astyrene, with reagent D, the unsaturated aliphatic carboxylic acidcompound, at a temperature within the range from about 50 C. to about300 C., preferably 80200 C., to effect acylation of the copolymer andthen adding reagents A and C and continuing the heating, the totalreaction time from about 0.5 to about 30 hours; and (3) heating reagentsA, B, and C, at a temperature within the range from about 50 C. to about300 C., preferably 150 C., and then effecting the acylation of suchintermediate product with reagent D, the unsaturated aliphaticcarboxylic acid compound, at temperatures within the range from about 50C. to about 300 C., preferably 200 C., the total reaction time beingfrom about 0.5 to about 30 hours.

Generally it is most convenient to conduct the process of this inventionin the presence of an inert, volatile solvent which serves to reduce theviscosity of the reaction mass. The solvent may remain in the finalproduct, if desired, to facilitate its application to metal surfaces.Any of the solvents ordinarily employed in the paint and varnishindustry may be used for the purpose such as, e.g., benzene, xylene,toluene, mesitylene, cyclohexane, methylcyclohexane, aromatic petroleumspirits, chlorobenzene, trichloroethylene, ethylene dichloride, dioxane,turpentine, diisopropyl ether, and the like. Mixtures of one or more ofthe foregoing may also be used. In some instances, however, it ispreferred to conduct the process in the absence of the solvent and then,optionally, to dilute the acylated organic phosphate complex with thedesired solvent or mixture of solvents prior to its application to ametal surface. This is generally the most advantageous and economicalprocedure in instances where the acylated organic phosphate complex isto be shipped to some distant point. It is also the preferred procedurein instances where the solvent employed in diluting the acylated organicphosphate complex is a solvent such as isobutyl alcohol or octyl alcoholwhich is chemically reactive with one or more of reagents A-D,inclusive.

The precise chemical composition of the acylated or ganic phosphatecomplex of this invention is not known. It is believed, however, thatthe phosphorus-containing reagent and the unsaturated aliphaticcarboxylic acid compound phosphorylate and acylate the organic hydroxycompounds present to form, respectively, acid phosphate ester groups andcarboxylic acid ester groups. Other reactants such as polymerizationand/or etherification may also occur during the process and it is notintended that the theories and evidence presented herein be interpretedin any manner which would limit the scope of the invention, except asdefined by the appended claims.

The following examples are presented to illustrate specific modes ofcarrying out the process of this invention.

All parts are by weight unless otherwise specified. The strong acidnumber is reported for the solvent-free acylated organic phosphatecomplex and is determined using bromphenol blue as the end pointindicator.

Example 1 210 parts (0.75 mole) of lineoleic acid, 288 parts (0.25 mole)of Polyol X450, 283 parts of xylene solvent, and 4 parts of paratoluenesulfonic acid catalyst are introduced into a reaction vessel andstirred thoroughly. The whole is then heated to about 143 C. andmaintained at this temperature for 4 hours while water of esterificationis removed by means of a side-arm water trap. The crude acylated PolyolX-450 thus obtained is washed with 500 parts of water to remove theesterification catalyst and then it is dried by azeotropic distillation,returning the xylene by means of a side-arm water trap.

949 parts (0.24 mole) of the acylated Polyol X450, 79 parts (0.48 mole)of Pentaphen, 36 parts (0.25 mole) of phosphorus pentoxide, and 115parts of xylene solvent arev reacted at the reflux temperature (ca. 143C.) for 6 hours.

The resulting 50 percent solution in xylene of the desired acylatedorganic phosphate complex shows the following analysis.

Percent phosphorus 1.28 Strong acid No. 49

Example 2 100 parts of the product of Example 1 is heated to 130 C./80mm. Hg to remove the xylene solvent and then 27 parts of isooctylalcohol is added. The resulting product is a 65 percent solution of theacylated organic phosphate complex in isooctyl alcohol.

Example 3 The experiment described in Example 1 is repeated, except thatisobutyl alcohol is employed in lieu of isooctyl alcohol. The product isa 65 percent solution of the acylated organic phosphate complex inisobutyl alcohol.

Example 4 575 parts (0.5 mole) of Polyol X450, 468 parts (0.5 mole) ofboiled linseed oil, 164 parts (1.0 mole) of Pentaphen, 71 parts (0.5mole) of phosphorus pentoxide, and 1278 parts of xylene are placed in aflask and stirred vigorously. The whole is refluxed for 6 hours whilewater is removed by means of a side-arm water trap. The product, a 50percent solution of the desired acylated organic phosphate complex inxylene, shows the following analysis.

Percent phosphorus 1.15 Strong acid No 42 Example 5 460 parts (0.4 mole)of Polyol X450 is acylated with 336 parts (1.2 moles) of linoleic acidin 775 parts of xylene solvent over a period of hours at the refluxtemperature.

1451 parts (0.38 mole) of the above acylated Polyol X450, 125 parts(0.76 mole) of Pentaphen, 54 parts (0.38 mole) of phosphorus pentoxide,and 179 parts of xylene solvent are heated for 8 hours at the refluxtemperature. The product, a 50 percent solution of the acylated organicphosphate complex in xylene solvent, shows the following analysis.

Percent phopsphorus 1.33 Strong acid No. 52

Example 6 575 parts (0.5 mole) of Polyol X450, 598 parts (2.0 moles) ofmethyl linoleate, 164 parts (1.0 mole) of Pentaphen, 71 parts (0.5 mole)of phosphorus pentoxide, and 1408 parts of xylene solvent are introducedinto a 6 reaction vessel and stirred vigorously. The whole is thenheated for 6 hours at the reflux temperature while water is removed bymeans of a side-arm water trap. The product, a 50 percent solution ofthe acylated organic phosphate complex in xylene solvent, shows thefollowing analysis.

Percent phosphorus 0.99 Strong acid No. 36

Example 7 575 parts (0.5 mole) of Polyol X450, 431 parts (1.5 moles) ofmethyl linoleate, 164 parts (1.0 mole) of Pentaphen, 71 parts (0.5 mole)of phophorus pentoxide, and 1241 parts of xylene solvent are introducedinto a reaction vessel and stirred vigorously. The whole is then heatedfor 6 hours at the reflux temperature and the water of reaction isremoved by means of a side-arm water trap. The product, a 50 percentsolution of the acylated organic phosphate complex in xylene solvent,shows hte following analysis.

Percent phosphorus 1.26 Strong acid No. 54

Example 8 575 parts (0.5 mole) of Polyol X450 is acylated with 140 parts(0.5 mole) of linoleic acid and 112 parts (0.5 mole) of tung oil acidsin 800 parts of xylene solvent over a period of 8 hours at the refluxtemperature. The water of esterification evolved is removed by means ofa side-arm water trap.

1500 parts (0.75 mole) of the above acylated Polyol X450, 249 parts(1.52 moles) of Pentaphen, 107 parts (0.75 mole) of phosphoruspentoxide, and 356 parts of xylene are introduced into a reaction vesseland stirred vigorously. The whole is then heated for 6 hours at thereflux temperature. The resulting product, a 50 percent solution of theacylated organic phosphate complex in xylene, shows the followinganalysis.

Percent phosphorus 2.19 Strong acid No. 76

Example 9 575 parts (0.5 mole) of Polyol X450 is acylated with 420 parts(1.5 moles) of linoleic acid in 968 parts of xylene solvent containing0.5 part of para toluenesulfonic acid as an esterification catalyst. Theacylation is effected by heating the whole for a period of 12 hours atthe reflux temperature while the water of esterification is removed bymeans of a side-arm water trap.

1271 parts (0.33 mole) of the above acylated Polyol X450, 492 parts (3.0moles) of Pentaphen, 142 parts 1.0 mole) of phosphorus pentoxide, and633 parts of xylene solvent are introduced into a reaction vessel andstirred vigorously. The whole is then heated at the reflux temperaturefor 6 hours to yield the product, a 50 percent solution of an acylatedorganic phosphate complex in xylene. It shows the following analysis.

Percent phosphorus 2.25 Strong acid No.

Example 10 522 parts (0.4 mole) of an acylated Polyol X450 prepared inthe manner set forth in Example 9, 392 parts (2.4 moles) of Pentaphen,114 parts (0.8 mole) of phosphorus pentoxide, and 506 parts of xylenesolvent are stirred together for 6 hours at about 143 C. The product, a50 percent solution of the acylated organic phosphate complex in xylene,shows the following analysis.

Percent phosphorus 3.01 Strong acid No. 112

7 Example 11 1042 parts (0.8 mole) of an acylated Polyol X-450 preparedin the manner set forth in Example 9, 197 parts (1.2 moles) ofPentaphen, 57 parts (0.4 mole) of phosphorus pentoxide, and 254 parts ofxylene are introduced into a reaction vessel and stirred vigorously. Thewhole is heated for hours at the reflux temperature while water isremoved by means of a side-arm water trap. The product, a 50 percentsolution of the acylated organic phosphate complex in xylene, shows thefollowing analysis.

Percent phosphorus 1.50 Strong acid No. 66

Example 12 750 parts (0.5 mole) of Polyol X-450 is acylated with 112parts (0.5 mole) of tung oil acids in xylene solution (853 parts ofxylene) over a period of 6 hours at the reflux temperature. The water ofesterification is removed by means of a side-arm water trap.

1355 parts (0.5 mole) of this acylated Polyol X-450, 246 parts (1.5moles) of Pentaphen, 71 parts (0.5 mole) of phosphorus pentoxide, and317 parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is stirred for 6 hours at the reflux temperaturewhile water is removed by means of a side-arm water trap. The product, a50 percent solution of the acylated organic phosphate complex in xylene,shows the following analysis.

Percent phosphorus 1.58 Strong acid No. 56

Example 13 460 parts (0.4 mole) of Polyol X450 is acylated with 336parts (1.2 moles) of linolenic acid in xylene solution over a period of6 hours at the reflux temperature. The water of esterification isremoved by means of a side-arm water trap.

1451 parts (0.38 mole) of the above acylated Polyol X450, 125 parts(0.76 mole) of Pentaphen, 54 parts (0.38 mole) of phosphorus pentoxide,and 179 parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is then refluxed for 6 hours while water isremoved by means of a side-arm water trap. The product, a 50 percentsolution of the acylated organic phosphate complex in xylene, shows thefol lowing analysis.

Percent phosphorus 1.31 Strong acid No. 56

Example 14 431 parts (0.375 mole) of Polyol X-450 is acylated with 140parts (0.50 mole) of linoleic acid in 864 parts of xylene solvent over aperiod of 7 hours at the reflux temperature while water ofesterification is removed by means of a side-arm water trap. Thereafter,231 parts (1.41 moles) of Pentaphen and 71 parts (0.50 mole) ofphosphorus pentoxide are added and the whole is refluxed for anadditional 7 hours. The product, a 50 percent solution of the acylatedorganic phosphate complex in xylene, shows the following analysis.

Percent phosphorus 1.83 Strong acid No. 76

Example 15 575 parts (0.50 mole) of Polyol X-450 is acylated with 110parts (0.39 mole) of linoleic acid in xylene solution over a period of 4hours at the reflux temperature while water of esterification is removedby means of a side-arm water trap.

1200 parts (0.44 mole) of this acylated Poyol X-450, 63 parts (0.39mole) of Pentaphen, 28 parts (0.20 mole) of phosphorus pentoxide, and 91parts of xylene are placed in a flask and stirred vigorously. The wholeis then heated 6 hours at the reflux temperature to prepare the product,which is a 50 percent solution in xylene of the desired acylated organicphosphate complex. It shows the following analysis.

Percent phosphorus 0.87 Strong acid No. 34

Example 16 575 parts (0.50 mole) of Polyol X450 is acylated with 187parts (0.67 mole) of linoleic acid in 750 parts of xylene solvent over aperiod of 6 hours at the reflux temperature. The water of esterificationis removed by means of a side-arm water trap.

1200 parts (0.40 mole) of this acylated Polyol X-450, 21 parts (0.13mole) of Pentaphen, 25 parts (0.18 mole) of phosphorus pentoxide, and 46parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is heated for 6 hours at the reflux temperature.The product, a 50 percent solution in xylene of the acylated organicphosphate complex, shows the following analysis.

Percent phosphorus 0.81 Strong acid No. 32 Example 17 575 parts (0.5mole) of Polyol X-450 is acylated with 746 parts (2.67 moles) oflinoleic acid in 1000 parts of xylene solvent over a period of 10 hoursat the reflux temperature. The water of esterification is removed bymeans of a side-arm water trap.

1890 parts (0.50 mole) of this acylate Polyol X-450, 63 parts (0.38mole) of Pentaphen, and 3 2 parts (0.23 mole) of phosphorus pentoxideare introduced into a flask and stirred vigorously. The whole is thenheated 6 hours at the reflux temperature. The product, a 58 percentsolution of the acylate organic phosphate complex in xylene, shows thefollowing analysis.

Percent phosphorus 0.76 Strong acid No. 31

Example 18 575 parts (0.50 mole) of Polyol X-450 is acylated with 287parts (1.0 mole) of tung oil acids in xylene solvent (844 parts) over aperiod of 8 hours at the reflux temperature. The water of esterificationis removed by means of a side-arm water trap.

1300 parts (0.39 mole) of this acylated Polyol X-450, 191 parts (1.16moles) of Pentaphen, 55 parts (0.39 mole) of phosphorus pentoxide, and246 parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is then refluxed for 4 hours. The product, a 50percent solution of the acylated organic phosphate complex in xylene,shows the following analysis.

Percent phosphorus 1.38 Strong acid No. 46

Example 19 575 parts (0.5 mole) of Polyol X-450 is acylated with 423parts (1.5 moles) of oleic acid in 971 parts of xylene solvent over aperiod of 8 hours at the reflux temperature. The water of esterificationis removed by means of a sidearm water trap.

1300 parts (0.34 mole) of this acylated Polyol X-450, 111 parts (0.68mole) of Pentaphen, 48 parts (0.34 mole) of phosphorus pentoxide, and159 parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is then refluxed for 8 hours at about C. while thewater of reaction is removed by means of a side-arm water trap. Theproduct, a 50 percent of the acylated organic phosphate complex inxylene, shows the following analysis.

Percent phosphorus 1.11 Strong acid No. 46

9 Example 20 575 parts (0.5 mole) of Polyol X-450 is acylated with 141parts (0.5 mole) of oleic acid in 707 parts of xylene solvent over aperiod of 8 hours at 140 C. The water of esterification is removed bymeans of a sidearm water trap.

1364 parts (0.48 mole) of this acylated Polyol X4SO, 237 parts (1.45mole) of Pentaphen, 68 parts (0.48 mole) of phosphorus pentoxide, and305 parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is then heated 8 hours at the reflux temperaturewhile the water of reaction is removed by means of a side-arm watertrap. The product, a 50 percent solution of the acylated organicphosphate complex in xylene, eshows the following ananysis.

Percent phosphorus 1.53 Strong acid No. 54

Example 21 1725 parts (1.5 moles) of Polyol X-450, 1260 parts (4.5moles) of linoleic acid, and 2904 parts of xylene solvent are refluxedfor 6 hours while the water of esteri fication is removed by means of aside-arm water trap.

5808 parts (1.5 moles) of the resulting acylated Polyol X450, 492 parts(3.0 moles) of Pentaphen, 214 parts (1.5 moles) of phosphorus pentoxide,and 706 parts of xylene solvent are introduced into a flask and stirredvigorously. The whole is then refluxed for 8 hours while the water ofreaction is removed by means of a side-arm water trap. The product, a 50percent solution of the desired acylated organic phosphate complex inxylene, shows the following analysis.

Percent phosphorus 1.27 Strong acid No. 60

Example 22 300 parts (0.26 mole) of Polyol X450 is acylated with 194parts (0.68 mole) of linoleic acid in 713 parts of xylene solvent over aperiod of 6 hours at the reflux temperature. The water of esterificationis removed by means of a side-arm water trap. 171 parts (1.04 moles) ofPentaphen and 48 parts (0.34 mole) of phosphorus pentoxide are added tothe reaction vessel and the whole is refluxed for an additional 6 hours,water being removed by means of a side-arm water trap. The product, a 50percent solution of the acylated organic phosphate complex in xylene,shows the following analysis.

Percent phosphorus 1.56 Strong acid No. 64

Example 23 575 parts (0.5 mole) of Polyol X-450 is acylated with 140parts (0.5 mole) of linoleic acid in 707. parts of xylene solventcontaining parts of para toluenesulfonic acid catalyst over a period of4 hours at the reflux temperature. The water of esterification isremoved by means of a side-arm water trap and the reaction mixture iswashed with warm water to remove the small amount of snlfonic acidcatalyst employed.

530 parts (0.32 mole) of this acylated Polyol X-450, 52 parts (0.32mole) of Pentaphen, 23 parts (0.16 mole) of phosphorus pentoxide, and 75parts of xylene are introduced into a flask and stirred vigorously. Thewhole is then heated the reflux temperature for about 6 hours. Theproduct, a 50 percent solution of the acylated organic phosphate complexin xylene, shows the following analysis.

Percent phosphorus 1.37 Strong acid No. 46

Example 24 549 parts (0.33 mole) of an acylated Polyol X-450 prepared inthe manner set forth in Example 23 above,

10 162 parts (0.99 mole.) of Pentaphen, 42 parts (0.33 mole) ofphosphorus pentoxide, and 400 parts of xylene solvent are introducedinto a flask and stirred vigorously. The whole is heated for 6 hours atthe reflux temperature to yield the desired product, a 42 percentsolution of the acylated organic phosphate complex in xylene. Theproduct has the following analysis.

Percent phosphorus 1.23 Strong acid No. 55

Example 25 1150 parts (1.0 mole) of Polyol X450, 852 parts (3.0 moles)of crude. linoleic acid derived. from tall OH, 2400 parts of xylenesolvent, 328 parts (2.0 moles) of Pentaphen, and 142 .parts (1.0 mole)of phosphorus pentoxide are introduced into a reaction flask fitted witha side-arm water trap. The whole is heated for 4.5 hours at the refluxtemperature to yield the product, a 50 percent solution of the acylatedorganic phosphate complex in xylene. It shows the fol-lowing analysis.

Percent phosphorus 1.14 Strong acid No 62 Example 26 863 parts (0.75mole) of Polyol X-450, 639 parts (2.25 moles) of crude linoleic acid,1700 parts of xylene solvent, 246 parts (1.5 moles) of Pentaphen, and142 parts (1.0 mole) of phosphorus pentoxide are introduced into a flaskequipped with a side-arm water trap. The whole is stirred and heated for9 hours at the reflux temperature while the Water of reaction is removedas formed. The product, a 52 percent solution of the acylated organicphosphate complex in xylene, shows the following analysis.

Percent phosphorus 1.54 Strong acid No. 48

Example 27 1150 parts (1.0 mole) of Polyol X-450, 852 parts (3.0 moles)of linoleic acid, 1209 parts of xylene solvent, 328 parts (2.0 moles) ofPentaphen, and 230 parts (2.0 moles) of commercial, percentorthophosphoric acid are introduced into a flask equipped with aside-arm water trap. The whole is stirred and heated at the refluxtemperature for 6.5 hours to yield the product, a 66.6 percent solutionof the acylated organic phosphate complex in xylene. It shows thefollowing analysis.

Percent phosphorus 1.21 Strong acid No. 45

Example 28 Percent phosphorus 2.47 Strong acid No. 60

Example 29 719 parts (0.625 mole) of Polyol X-450, 164 parts (1.0 mole)of Pentaphen, and 71 parts (0.5 mole) of phosphorus pentoxide, and 952parts of xylene solvent are introduced into a flask fitted with astirrer and a sidearm water trap. The whole is refluxed for 6 hourswhile the water of reaction is removed as formed.

494 parts (0.641 mole) of the resulting organic phosphate complex isacylated with 179 parts (0.641 mole) of linoleic acid over a 7 hourperiod at 154 C. The water of esterification is removed as formed bymeans of a side-arm water trap. The product, a 63 percent solution ofthe acylated organic phosphate complex in xylene, shows the followinganalysis.

Percent phosphorus 1.02 Strong acid No 32 Example 30 2155 parts (1.875moles) of Polyol X-450 is acylated with 706 parts (2.5 moles) of crudelinoleic acid derived from tall oil in 2310 parts of xylene solvent overa period of hours at 147 C. The water of esterification is removed bymeans of a side-arm water trap. Thereafter 1155 parts (7.05 moles) ofPentaphen and 355 parts (2.5 moles) of phosphorus pentoxide are addedand the whole is heated for an additional 2 hours at 151 C. The product,a 65 percent solution of the acylated organic phosphate complex inxylene, shows the following analysis.

Percent phosphorus 2.26

Strong acid No. 59

Example 31 383 parts (0.33 mole) of Polyol X-450, 284 parts (1.0 mole)of linoleic acid, and 5 ml. of commercial, 85 percent phosphoric acidare heated for 3 hours at 140- 147 C. while the water of esterificationis permitted to escape from the reaction vessel. Thereafter, 109 parts(0.66 mole) of Pentaphen and 77 parts (0.66 mole) of commercial, 85percent phosphoric acid are added and the whole is heated for anadditional 14.5 hours at 143-l50 C., While the water of reaction isremoved as formed by means of a side-arm water trap. The solventfree,acylated organic phosphate complex is diluted with 254 .parts ofaromatic petroleum spirits to lessen its viscosity. The product showsthe following analysis.

Percent phosphorus 2.11 Strong acid No. 69

Example 32 863 parts (0.75 mole) of Polyol X-450 is acylated with 639parts (2.25 moles) of linoleic acid in 1461 parts of xylene solvent overa period of 7.5 hours at 142-144 C. The water of esterification isremoved as formed by means of a side-arm water trap. Thereafter, 246parts (1.5 moles) of Pentaphen, 388 parts of xylene solvent, and 142parts mole) of phosphorus pentoxide are added and the whole is heatedfor an additional 6 hours at 143 C. The water of reaction is removed bymeans of the side-arm water trap. The product, a 50 percent solution ofthe acylated organic phosphate complex in xylene, shows the followinganalysis.

Percent phosphorus 1.42 Strong acid No. 72

Example 33 383 parts (0.33 mole) of Polyol X-450 is acylated with 284parts (1.0 mole) of linoleic acid in the presence of 5 ml. ofcommercial, 85 percent phosphoric acid as catalyst over a period ofabout 2.5 hours at 140-150 C. The water of esterification evolved iscollected by means of a side-arm water trap. Thereafter, 109 parts (0.66mole) of Pentaphen and 47.5 parts (0.33 mole) of phosphorus pentoxideare added and the whole is heated for one hour at 130152 C. and anadditional 3.5 hours at 103-l29 C. The viscous, acylated organicphosphate complex is diluted with 258 parts of aromatic petroleumspirits to facilitate handling. The product shows the followinganalysis.

Percent phosphorus 1.94 Strong acid No 53 A number of laboratory andoutdoor exposure tests were carried out to determine the utility of thehereindescribed acylated organic phosphate complexes as protectivecoating compositions per se for metals and as ingredients in siccativeorganic coating compositions such as paints, varnishes, lacquers,primers, synthetic resins, enamels, etc. They are also useful asingredients in water base or emulsion paints such as synthetic latexpaints derived from acrylic resins, polyvinyl alcohol resins, alkydresins, etc., by emulsification thereof with water, as well aswater-soluble paints or primers derived from water-soluble alkyd resins,acrylic resins, and the like. The complexes of this invention may beapplied to metal surfaces by any one of the methods ordinarily used inthe paint and varnish industry such as brushing, spraying, dip-coating,flow-coating, roller-coating, and the like. The viscosity of the complexor the coating composition containing the complex may be adjusted forthe particular method of application selected by adding a suitableamount of a solvent such as benzene, xylene, mesitylene, aromaticpetroleum spirits, turpentine, or other appropriate solvents. The metalsurface which has been thus coated is then dried either by exposure toair or by means of a baking procedure. A dried film thickness of thecomplex or the coating composition containing the complex ranging fromabout 0.01 mil to about 4 mils, preferably 0.02-2 mils, is usuallyrequired to provide adequate protection for the metal surface. Coatingsheavier than 4 mils can be used, if desired, but they normallycontribute little in the way of additional protection. In someinstances, it is desirable to admix the complex with a pigment such astitanium dioxide, chrome green, aluminum powder, carbon black, ironoxide, or zinc chromate. In some instances it is also desirable toinclude conventional improving agents such as pigment extenders,anti-skinning agents, driers, gloss agents, color stabilizers, etc.

Example A Three 4-inch x 8-inch panels of clean, degreased, galvanized,20-gauge SAE 1020 cold-rolled steel were coated in the manner set forthbelow; scribed with a pointed instrument to yield a V beginning one inchfrom a bottom corner of the panel, extending to one inch from theopposite side, and returning to a point one inch from the other bottomcorner; and then exposed at a 45 angle for a period of one year to theweather prevailing in the Great Lakes region of the United States.

Thereafter, the panels were inspected for loss of the coating in thearea adjacent to the scribe or score. The latter, designated as theundercut rating, is the average loss of coating from each side of thescribe expressed as an integer which represents the number ofthirtyseconds of an inch of such loss.

It will be noted that a complex of this invention was substantially moreeffective than a widely used commercial primer in reducing the extent ofundercutting, despite the fact that the film thickness of the complexwas only one-tenth that of the commercial primer.

Example B Four 4-inch x 8-inch panels of clean, degreased, 20- gauge SAE1020 cold-rolled steel were brush-coated, re-

13 spectively, with four different aluminum pigmented paints to yieldfilms having a dry thickness of 0.5-* -0.1 mil. Each panel was V-scribedon the front face and then exposed at a 45 angle for a period of 15months to the Weather prevailing in the Great Lakes region. The frontand rear faces of each panel were inspected for rusting and rated on ascale of to 10, zero denoting a completely rusted panel and 10 denotinga rust-free panel.

It will be noted that an aluminum-pigmented complex of this inventionwas superior to three known aluminumpigmented paints in inhibiting therusting of plain steel.

Example C Three 4-inch x 8-inch panels of rusted, ZO-gauge SAE 1020cold-rolled steel (rusted by exposure to the weather for 2 months) wereprovided, respectively, with films of 1.7:02 mil thickness (measured onthe dried film) of several protective coating compositions. The coated,pre-rusted panels were then exposed at a 45 angle for one year to theweather prevailing in the Great Lakes region and inspected for abreak-through of the rust. The front and rear faces of each panel weregiven a rerust rating on a scale of zero to 10, zero denoting acompletely re-rusted panel and 10 denoting a rust-free panel (i.e., freefrom visible surface rust).

Outdoor Exposure Test, Re-rust Rating Protective Coating CompositionFront Rear face face Equal parts by weight of a commercial alkyd sparvarnish and the product of Example 1 10 10 Equal parts by weight oflinseed oil and the product of Example 1 9 10 Commercial plasticizedorganic phosphate paint. 0 1

The above results point out the utility of the complexes of the presentinvention as rust-inhibiting ingredients in known siccative organiccoating compositions.

Example D Five pre-rusted, 4-inch x 8-inch panels of 20-gauge SAE 1020cold-rolled steel were brush-coated, respectively, with differentprimers, brush-coated with a good, commercial, white enamel, and thenexposed at a 45 angle for 17 months to the weather prevailing in theGreat Lakes region. The front and rear faces of each panel wereinspected for a break-through of the rust and rated as in Example C.

The above results point out the utility of the complexes of thisinvention as primers for pre-rusted steel which is to receive a top-coatof a known siccative organic finish.

Example E Three Z-foot sections of degreased, 2-inch x 2-inch x 43-inchhot-rolled angle iron were brush-coated, respectively, with threedifferent protective coating compositions to yield a film, when dry, of2:0.3 mil thickness. The coated angle irons were exposed in inverted-Vfashion for 4 months to the weather prevailing in the Great Lakes regionand then inspected for the condition of the coating and the developmentof rust.

Protective Coating Composition Outdoor Exposure Test,

Inspectors Remarks Coating has become chalky; rust developing beneath ithas Stained the coating.

Another commercial organic Do.

phosphate resin.

Product of Example 21 Commercial organic phosphate resin.

Coating is clear and hard; no rust beneath it.

These results illustrate the utility of the complexes of this inventionas protective coating materials per se for hot-rolled, heavy-gauge iron.

Example F Three Meehanite (calcium silicide-treated cast iron) castingshaving the form of an open box were dip-coated, respectively, in threedifferent protective coating compositions, allowed to air-dry, and thenexposed with the open side inverted for 3.5 months to the weatherprevailing in the Great Lakes region. The castings were then visuallyinspected to determine the extent to which they had rusted.

Outdoor exposure test, percent of total Protective coating composition:area rusted Commercial alkyd spar varnish 50 Commercial organicphosphate resin 30 Product of Example 21 10 Example G Water ImmersionTest, Condition of Coating on Panel Immersed at Protective CoatingComposition Ambient temperature Commercial organic phosphate Surfacecovered Surface turned resin. with loose white and powder. powdery.Product of Example 21 Surface clear Surface lost and hard. some of itsgloss. Product of Example 18 ..do D0.

The above test results show the ability of the complexes of the presentinvention to withstand deterioration in the presence of Water.

Example H Three 4-inch x 8-inch panels of clean, degreased, 20- gaugeSAE 1020 cold-rolled steel were spray-coated, respectively, with threedifferent chrome green-pigmented coating compositions and allowed to airdry. Thereafter, each coated panel was line-scribed with a pointedinstrument to yield a vertical scribe beginning one-inch from 1 5 thetop of the panel and ending one inch from the bottom thereof.

The coated and scribed panels were subjected to a Salt Fog Corrosiontest for 120 hours. The apparatus used for this test is described inASTM procedure Bll7-57T. It consists of a chamber in which a mist or fogof 5 percent aqueous sodium chloride solution is maintained in contactwith the panels at 95i2 F. The panels were then removed from the chamberand scraped vigorously with a putty knife to remove any coating whichhad separated from the metal substrate. Each panel was inspected todetermine the percent of the total area thereof which was still coveredwith an adherent coating (reported as elcnt Of cOatin adheled).

Salt fog COII'OSlOll test ercent of Protective coating composition: fiadhered In addition to their utility as protective coating materials forferrous metals, the acylated organic phosphate complexes of thisinvention are useful in protecting non-fer rous metals and alloysthereof such as aluminum, magnesium, copper, brass, bronze, white metal,etc., against corrosion. They are also useful as protective coatingmaterials on galvanized ferrous surfaces, on plated metal surfaces suchas, e.g., copper-plated, nickel-plated, and cadrnium-plated ferroussurfaces, and on phosphated metal surfaces. They are also useful asprotective coating materials on chromated aluminum or chnomated zincsurfaces, i.e., aluminum or zinc surfaces which have been treated withan aqueous solution of chromic acid and/ or a derivative thereof such asa metal chromate or dichromate, an amine chromate, ammonium chromate,etc. Particularly fine results are obtained when the coatingcompositions of the present invention are applied over a metal surfacewhich has been phosphated by means of a novel aqueous phosphatingsolution containing as essential ingredients zinc ion, phosphate ion,nitrate ion, and a cation selected from the group consisting of lithium,beryllium, magnesium, calcium, strontium, cadmium, and barium. Suchphosphating solutions, which provide a dense, adherent,micro-crystalline or amorphous phosphate coating upon the metalsubstrate, are described in detail in copending US. application, Ser.No. 373,449, now US. Patent 3,090,709, filed August 10, 1953. It isintended that the entire disclosure of Ser. No. 373,449 be incorporatedherein by reference.

What is claimed is:

1. An acylated organic phosphate complex prepared by the process whichcomprises the reaction of:

(A) one mole of a phosphorus-containing reagent selected from the groupconsisting of phosphorus pentoxide and phosphoric acids,

(B) from about 0.2 to about 5 moles of a co-polymer of allyl alcohol anda styrene,

(C) from about 0.5 to about 5 moles of an alkylphenol,

and

(D) from about 0.5 to about 4 moles per mole of (B) employed of anunsaturated aliphatic mono-carboxylic acid compound selected from thegroup consisting of high molecular weight unsaturated aliphaticcarboxylic acids containing at least about 12 carbon atoms and esters ofsuch acids, at a temperature within the range from about 50 C. to about300 C. for about 0.5 to about 30 hours.

2. A complex in accordance with claim 1 characterized further in thatthe phosphorus-containing reagent of (A) is phosphorus pentoxide.

3. A complex in accordance with claim 1 characterized further in thatthe copolymer of (B) is a copolymer of about equimolar amounts of allylalcohol and styrene and has an average molecular weight in the rangefrom about 500 to about 5,000.

4. A complex in accordance with claim 1 characterized further in thatthe alkylphenol of (C) is para-tertiary amylphenol.

5. A complex in accordance with claim 1 characterized further in thatthe unsaturated aliphatic carboxylic acid compound of (D) is linoleicacid.

6. A complex in accordance with claim 1 characterized further in thatthe copolymer of (B) is first acylated with the unsaturated aliphaticcarboxylic acid compound of (D) and then such acylated copolymer isreacted with the phosphorus-containing reagent of (A) and thealkylphenol of (C).

7. A method for inhibiting the corrosion of a metal surface whichconsists of applying thereto a film comprising the complex of claim 1.

8. A method in accordance with claim 7 wherein said film comprises amajor proportion of a siccative organic coating composition and a min-orproportion of the complex of claim 1.

9. A method in accordance with claim 7 characterized further in that themetal surface is a ferrous metal surface.

10. A metal article the metal surface of which has been protectedagainst corrosion in accordance with the method of claim 7.

11. A metal article the metal surface of which has been protectedagainst corrosion in accordance with the method of claim 8.

References Cited by the Examiner UNITED STATES PATENTS 2,005,619 6/35Graves 252-32.5 2,894,938 7/59 Chapin et a1 260-881 3,055,865 9/62 Craig106-14 FOREIGN PATENTS 757,043 9/ 56 Great Britain.

LEON I. BERCOVITZ, Primary Examiner. ALPHONSO D. SULLIVAN, Examiner.

1. AN ACYLATED ORGANIC PHOSPHATE COMPLEX PREPARED BY THE PROCESS WHICHCOMPRISES THE REACTION OF: (A) ONE MOLE OF A PHOSPHORUS-CONTAININGREAGENT SELECTED FROM THE GROUP CONSISTING OF PHOSPHORUS PENTOFIXDE ANDPHOSPHORIC ACIDS, (B) FROM ABOUT 0.2 TO ABOUT 5 MOLES OF A CO-POLYMER OFALLYL ALCOHOL AND A STYRENE, (C) FROM ABOUT 0.5 TO ABOUT 5 MOLES OF ANALKYLPHENOL, AND (D) FROM ABOUT 0.5 TO ABOUT 4 MOLES PER MOLE OF (B)EMPLOYED OF AN UNSATURATED ALIPHATIC MONO-CARBOXYLIC ACID COMPOUNDSELECTED FROM THE GROUP CONSISTING OF HIGH MOLECULAR WEIGHT UNSATURATEDALIPHATIC CARBOXYLIC ACIDS CONTAINING AT LEAST ABOUT 12 CARBON ATOMS ANDESTERS OF SUCH ACIDS, AT A TEMPERATURE WITHIN THE RANGE FROM ABOUT 50*C.TO ABOUT 300*C. FOR ABOUT 0.5 TO ABOUT 30 HOURS.